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![Joel Granados](/assets/img/avatar_default.png)
We make these changes in order to prepare __register_sysctl_table and its callers for when we remove the sentinel element (empty element at the end of ctl_table arrays). We don't actually remove any sentinels in this commit, but we *do* make sure to use ARRAY_SIZE so the table_size is available when the removal occurs. We add a table_size argument to __register_sysctl_table and adjust callers, all of which pass ctl_table pointers and need an explicit call to ARRAY_SIZE. We implement a size calculation in register_net_sysctl in order to forward the size of the array pointer received from the network register calls. The new table_size argument does not yet have any effect in the init_header call which is still dependent on the sentinel's presence. table_size *does* however drive the `kzalloc` allocation in __register_sysctl_table with no adverse effects as the allocated memory is either one element greater than the calculated ctl_table array (for the calls in ipc_sysctl.c, mq_sysctl.c and ucount.c) or the exact size of the calculated ctl_table array (for the call from sysctl_net.c and register_sysctl). This approach will allows us to "just" remove the sentinel without further changes to __register_sysctl_table as table_size will represent the exact size for all the callers at that point. Signed-off-by: Joel Granados <j.granados@samsung.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
304 lines
7.3 KiB
C
304 lines
7.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2007
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*
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* Author: Eric Biederman <ebiederm@xmision.com>
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*/
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#include <linux/module.h>
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#include <linux/ipc.h>
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#include <linux/nsproxy.h>
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#include <linux/sysctl.h>
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#include <linux/uaccess.h>
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#include <linux/capability.h>
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#include <linux/ipc_namespace.h>
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#include <linux/msg.h>
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#include <linux/slab.h>
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#include "util.h"
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static int proc_ipc_dointvec_minmax_orphans(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ipc_namespace *ns =
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container_of(table->data, struct ipc_namespace, shm_rmid_forced);
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int err;
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err = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
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if (err < 0)
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return err;
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if (ns->shm_rmid_forced)
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shm_destroy_orphaned(ns);
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return err;
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}
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static int proc_ipc_auto_msgmni(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ctl_table ipc_table;
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int dummy = 0;
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memcpy(&ipc_table, table, sizeof(ipc_table));
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ipc_table.data = &dummy;
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if (write)
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pr_info_once("writing to auto_msgmni has no effect");
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return proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
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}
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static int proc_ipc_sem_dointvec(struct ctl_table *table, int write,
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void *buffer, size_t *lenp, loff_t *ppos)
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{
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struct ipc_namespace *ns =
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container_of(table->data, struct ipc_namespace, sem_ctls);
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int ret, semmni;
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semmni = ns->sem_ctls[3];
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ret = proc_dointvec(table, write, buffer, lenp, ppos);
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if (!ret)
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ret = sem_check_semmni(ns);
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/*
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* Reset the semmni value if an error happens.
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*/
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if (ret)
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ns->sem_ctls[3] = semmni;
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return ret;
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}
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int ipc_mni = IPCMNI;
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int ipc_mni_shift = IPCMNI_SHIFT;
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int ipc_min_cycle = RADIX_TREE_MAP_SIZE;
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static struct ctl_table ipc_sysctls[] = {
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{
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.procname = "shmmax",
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.data = &init_ipc_ns.shm_ctlmax,
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.maxlen = sizeof(init_ipc_ns.shm_ctlmax),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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},
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{
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.procname = "shmall",
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.data = &init_ipc_ns.shm_ctlall,
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.maxlen = sizeof(init_ipc_ns.shm_ctlall),
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.mode = 0644,
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.proc_handler = proc_doulongvec_minmax,
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},
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{
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.procname = "shmmni",
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.data = &init_ipc_ns.shm_ctlmni,
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.maxlen = sizeof(init_ipc_ns.shm_ctlmni),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &ipc_mni,
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},
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{
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.procname = "shm_rmid_forced",
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.data = &init_ipc_ns.shm_rmid_forced,
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.maxlen = sizeof(init_ipc_ns.shm_rmid_forced),
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.mode = 0644,
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.proc_handler = proc_ipc_dointvec_minmax_orphans,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_ONE,
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},
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{
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.procname = "msgmax",
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.data = &init_ipc_ns.msg_ctlmax,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmax),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "msgmni",
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.data = &init_ipc_ns.msg_ctlmni,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmni),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = &ipc_mni,
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},
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{
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.procname = "auto_msgmni",
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.data = NULL,
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.maxlen = sizeof(int),
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.mode = 0644,
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.proc_handler = proc_ipc_auto_msgmni,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_ONE,
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},
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{
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.procname = "msgmnb",
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.data = &init_ipc_ns.msg_ctlmnb,
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.maxlen = sizeof(init_ipc_ns.msg_ctlmnb),
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.mode = 0644,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "sem",
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.data = &init_ipc_ns.sem_ctls,
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.maxlen = 4*sizeof(int),
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.mode = 0644,
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.proc_handler = proc_ipc_sem_dointvec,
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},
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#ifdef CONFIG_CHECKPOINT_RESTORE
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{
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.procname = "sem_next_id",
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.data = &init_ipc_ns.ids[IPC_SEM_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_SEM_IDS].next_id),
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.mode = 0444,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "msg_next_id",
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.data = &init_ipc_ns.ids[IPC_MSG_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_MSG_IDS].next_id),
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.mode = 0444,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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{
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.procname = "shm_next_id",
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.data = &init_ipc_ns.ids[IPC_SHM_IDS].next_id,
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.maxlen = sizeof(init_ipc_ns.ids[IPC_SHM_IDS].next_id),
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.mode = 0444,
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.proc_handler = proc_dointvec_minmax,
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.extra1 = SYSCTL_ZERO,
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.extra2 = SYSCTL_INT_MAX,
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},
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#endif
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{}
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};
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static struct ctl_table_set *set_lookup(struct ctl_table_root *root)
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{
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return ¤t->nsproxy->ipc_ns->ipc_set;
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}
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static int set_is_seen(struct ctl_table_set *set)
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{
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return ¤t->nsproxy->ipc_ns->ipc_set == set;
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}
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static int ipc_permissions(struct ctl_table_header *head, struct ctl_table *table)
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{
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int mode = table->mode;
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#ifdef CONFIG_CHECKPOINT_RESTORE
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struct ipc_namespace *ns = current->nsproxy->ipc_ns;
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if (((table->data == &ns->ids[IPC_SEM_IDS].next_id) ||
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(table->data == &ns->ids[IPC_MSG_IDS].next_id) ||
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(table->data == &ns->ids[IPC_SHM_IDS].next_id)) &&
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checkpoint_restore_ns_capable(ns->user_ns))
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mode = 0666;
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#endif
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return mode;
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}
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static struct ctl_table_root set_root = {
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.lookup = set_lookup,
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.permissions = ipc_permissions,
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};
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bool setup_ipc_sysctls(struct ipc_namespace *ns)
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{
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struct ctl_table *tbl;
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setup_sysctl_set(&ns->ipc_set, &set_root, set_is_seen);
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tbl = kmemdup(ipc_sysctls, sizeof(ipc_sysctls), GFP_KERNEL);
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if (tbl) {
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int i;
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for (i = 0; i < ARRAY_SIZE(ipc_sysctls); i++) {
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if (tbl[i].data == &init_ipc_ns.shm_ctlmax)
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tbl[i].data = &ns->shm_ctlmax;
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else if (tbl[i].data == &init_ipc_ns.shm_ctlall)
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tbl[i].data = &ns->shm_ctlall;
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else if (tbl[i].data == &init_ipc_ns.shm_ctlmni)
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tbl[i].data = &ns->shm_ctlmni;
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else if (tbl[i].data == &init_ipc_ns.shm_rmid_forced)
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tbl[i].data = &ns->shm_rmid_forced;
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else if (tbl[i].data == &init_ipc_ns.msg_ctlmax)
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tbl[i].data = &ns->msg_ctlmax;
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else if (tbl[i].data == &init_ipc_ns.msg_ctlmni)
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tbl[i].data = &ns->msg_ctlmni;
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else if (tbl[i].data == &init_ipc_ns.msg_ctlmnb)
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tbl[i].data = &ns->msg_ctlmnb;
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else if (tbl[i].data == &init_ipc_ns.sem_ctls)
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tbl[i].data = &ns->sem_ctls;
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#ifdef CONFIG_CHECKPOINT_RESTORE
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else if (tbl[i].data == &init_ipc_ns.ids[IPC_SEM_IDS].next_id)
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tbl[i].data = &ns->ids[IPC_SEM_IDS].next_id;
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else if (tbl[i].data == &init_ipc_ns.ids[IPC_MSG_IDS].next_id)
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tbl[i].data = &ns->ids[IPC_MSG_IDS].next_id;
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else if (tbl[i].data == &init_ipc_ns.ids[IPC_SHM_IDS].next_id)
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tbl[i].data = &ns->ids[IPC_SHM_IDS].next_id;
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#endif
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else
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tbl[i].data = NULL;
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}
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ns->ipc_sysctls = __register_sysctl_table(&ns->ipc_set,
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"kernel", tbl,
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ARRAY_SIZE(ipc_sysctls));
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}
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if (!ns->ipc_sysctls) {
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kfree(tbl);
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retire_sysctl_set(&ns->ipc_set);
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return false;
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}
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return true;
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}
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void retire_ipc_sysctls(struct ipc_namespace *ns)
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{
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struct ctl_table *tbl;
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tbl = ns->ipc_sysctls->ctl_table_arg;
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unregister_sysctl_table(ns->ipc_sysctls);
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retire_sysctl_set(&ns->ipc_set);
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kfree(tbl);
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}
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static int __init ipc_sysctl_init(void)
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{
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if (!setup_ipc_sysctls(&init_ipc_ns)) {
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pr_warn("ipc sysctl registration failed\n");
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return -ENOMEM;
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}
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return 0;
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}
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device_initcall(ipc_sysctl_init);
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static int __init ipc_mni_extend(char *str)
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{
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ipc_mni = IPCMNI_EXTEND;
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ipc_mni_shift = IPCMNI_EXTEND_SHIFT;
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ipc_min_cycle = IPCMNI_EXTEND_MIN_CYCLE;
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pr_info("IPCMNI extended to %d.\n", ipc_mni);
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return 0;
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}
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early_param("ipcmni_extend", ipc_mni_extend);
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